On Thu, Jan 12, 2023 at 01:47:03PM -0600, Rob Herring wrote:
> On Thu, Jan 12, 2023 at 6:59 AM Qun-Wei Lin <qun-wei.lin@xxxxxxxxxxxx> wrote:
> >
> > The "dma-ranges" property value is a sequence of
> > child-address parent-address child-size
> >
> > The size of each field is determined by taking the child's
> > "#address-cells" value, the parent's "#address-cells" value,
> > and the child's "#size-cells" value.
> >
> > However, in the following example, it gives a false alarm:
> > +-----------------------------------+---------------------------------------+
> > | ranges.dts | dma-ranges.dts |
> > +-----------------------------------+---------------------------------------+
> > | /dts-v1/; | /dts-v1/; |
> > | | |
> > | /{ | /{ |
> > | #address-cells = <1>; | #address-cells = <1>; |
> > | | |
> > | parent { | parent { |
> > | #address-cells = <1>; | #address-cells = <1>; |
> > | #size-cells = <1>; | #size-cells = <1>; |
> > | ranges = <0x0 0xe000 0x1000>; | dma-ranges = <0x0 0xe000 0x1000>; |
> > | child { | child { |
> > | ... | ... |
> > | }; | }; |
> > | }; | }; |
> > | }; | }; |
> > +-----------------------------------+---------------------------------------+
> > | no warning | Warning (avoid_unnecessary_addr_size) |
> > +-----------------------------------+---------------------------------------+
> >
> > Same as "ranges", it should not be reported in this check.
>
> Except that dma-ranges only makes sense if there is a ranges property.
Hm, does it? It would certainly be an odd situation, but I can
imagine a sort of bus that can DMA, but which has no-addressable
registers on it.
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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